1. Field of the Invention
This invention relates to a coupler made of a flexible material and designed for coupling two or more plaques by introducing said coupler into aligned bores of said plaques.
2. Prior Art
There have been known various couplers of this category including those disclosed in Japanese Pat. Publication Nos. 58-3924, 62-2325 and 60-21537 as well as in Japanese Pat. Disclosure No. 62-246609 and Japanese Utility Design Disclosure No. 61-50810.
All the couplers disclosed in the above cited documents consists of two separate components, of which one is a cap body for being fitted into aligned bores of the plaques to be coupled by the couple and the other is a pin body for being introduced into a central recess of said cap body. Two or more plaques can be coupled together by introducing the pin body into the cap body which has been fitted into aligned bores of the plaques as a ring-shaped projection formed on said pin body outwardly pushes the cap body so that the cap body is accordingly expanded outwards and pressed hard against the side wall of the aligned bores to hold the plaques together in a coupled condition.
Therefore, any of the couplers as described above can not achieve the objective of coupling plaques until two separate components are brought to an interlocked condition in some way or another.
For manufacturing such couplers, the number of manufacturing steps is inevitably large because at least two separate components are involved for each unit. This in turn offers a high probability of missing components during manufacturing and shipping as well as in actual coupling operations. Moreover, interlocking two separate components entails strict dimensional requirements to be observed for precision.
In order to get rid of the above and other problems, there have been proposed integrally formed couplers or couplers having only one component.
FIGS. 9(a) and (b) of the accompanying drawings illustrate a one-component coupler disclosed in U.S. Pat. No. 4,122,583. As shown in FIG. 9(a), a coupler according to this document comprises a trunk body 1 for holding a plaque a and a leg body 2 for holding a panel b to form an integral unit of coupler, said leg body 2 having a pair of flanges 4, 4 extending radially from the lower end of said trunk body 1 and connected respectively by hinges 3, 3 with it. As illustrated in FIG. 9(b), when the trunk body 1 is pushed down, said hinges 3, 3 are broken and the trunk body 1 goes down through the panel b until the lower end of the trunk body 1 and the flanges 4, 4 are firmly fitted onto the upper surface of the panel b as a pair of arms 6, 6 articulated by three pairs of hinges 5a, 5a, 5b, 5b and 5c, 5c are bent upward to support the respective flanges.
Since the coupler as described above is so designed as to rigidly hold the panel b when the trunk body 1 pushed down and the hinges 3, 3 are broken by the downward motion of the trunk body 1, the coupler is irreversibly deformed, and cannot be reused. Moreover, since the leg body 2 comprises pairs of hinges 5a, 5a, 5b, 5b and 5c, 5c, it is mechanically fragile and does not have enough resistance against external force and/or vibration when it is in use. These and other problems that accompany a coupler according to the above teaching make it poor for practical applications.
FIGS. 10(a), 10(b) and 10(c) of the accompanying drawings illustrate another coupler disclosed in U.S. Pat. No. 4,377,358.
As best seen in FIG. 10(a), another coupler comprises a pair of flanges, between which is an axial rod 8 which is cleaved to form a pair of branch arms 9, 9 extending downwardly, which are then bent upward as that both ends of the branch arms 9, 9 are connected to the respective flanges 7, 7.
After the flanges 7, 7 are put together as shown in FIG. 10(b), the axial rod 8 is pushed down as shown in FIG. 10(c) to laterally extend the branch arms 9, 9 which then presses plaques a and a' upward to rigidly couple them. At this stage, notched sections 9a, 9a of the branch arms 9, 9 are interlocked with a catch 8a of the axial rod 8.
With such an arrangement, if it is tried to forcibly remove the coupler from the plaques a and a' to reuse the unit, it can be easily damaged as the load placed by the plaques on the unit is by far larger than the one applied by the plaques when the unit is introduced into the aligned bores of the plaques, making any reuse of the unit practically impossible.
Moreover, a coupler as illustrated in FIG. 9 can not be temporarily, but securely, held in the bore of the panel b when the leg body 2 is introduced therein and consequently it can drop from the panel b at any time when it is in the bore, being very unstable during the operation of receiving the trunk body 1 from above. Similarly, a coupler illustrated in FIG. 10 can not be securely held in the aligned bores of the plaques a, a' until the axial rod 8 is thrusted into the aligned bores. Therefore it is precariously contained as shown in FIG. 10(b).
It is, therefore, an object of the present invention to provide a coupler in the form of an integral unit and, hence, free from any troublesome operation of combining two or more components or any risk of finding missing any components when coupling plaques, and which is capable of being temporarily, but securely, held in aligned bores of the plaques and/or panels to be coupled by the coupler, eliminating any possibility for the components to unintentionally come loose from the bores and consequently securely pushed into the bores of the plaques.
It is another object of the invention to provide a coupler with which the load charged thereto at the time of removing it from aligned bores of plaques is not significantly greater than the load applied thereto at the time of introducing it into the aligned bores so that it can be easily removed from the plaques for reuse whenever necessary without causing damages to the coupler.